tjLoadImage(): Fix FPE triggered by malformed BMP In rdbmp.c, it is necessary to guard against 32-bit overflow/wraparound when allocating the row buffer, because since BMP files have 32-bit width and height fields, the value of biWidth can be up to 4294967295. Specifically, if biWidth is 1073741824 and cinfo->input_components = 4, then the samplesperrow argument in alloc_sarray() would wrap around to 0, and a division by zero error would occur at line 458 in jmemmgr.c. If biWidth is set to a higher value, then samplesperrow would wrap around to a small number, which would likely cause a buffer overflow (this has not been tested or verified.)